Vehicle foot brake locking mechanism; foot brake locking mechanism release means; and parking brake locking mechanism release means

ABSTRACT

An electrical mechanism for locking the foot brake of a motor vehicle, including a solenoid which causes the foot brake to be locked in position and an electrical relay system comprises of a circuit which, when completed, actuates the solenoid; the relay system circuit includes the vehicle ignition switch, a stop light switch which is closed when the foot brake is operated and the vehicle rear stop lights are lit; a first switch which is closed when the automatic locking mechanism has not been activated; three second switches in electric parallel, a first one that is associated with the gear shift lever and is closed when the gear shift lever is in Neutral gear, a second one that may be closed by the vehicle operator if he desires the foot brake to automatically lock, and a third inertia controlled safety switch that is closed only after the vehicle has come to a full stop when there has been a rapid deceleration of the vehicle. The foot brake locking mechanism release means comprises a solenoid, which, when activated, causes release of the foot brake locking mechanism and a second relay system circuit associated with this solenoid, which second circuit must be completed to activate the solenoid; the second circuit includes the vehicle ignition switch, a second switch which is closed only when the gear shift lever is in one of the driving gears, a third switch which is closed when the motor is operating, a fourth switch which is closed only when the foot brake is locked, a fifth switch which is closed just as the vehicle operator initiates movement of the vehicle, and in parallel with each other there are a vacuum switch connected with the vehicle motor induction manifold to be closed upon pressure reduction in this manifold and a gravity controlled switch means which is closed when the vehicle is on a level surface and is open when the vehicle is facing uphill or downhill. The parking brake locking mechanism release means also comprises a solenoid which, when actuated, releases the parking brake and a third relay system circuit, which must be completed to activate the solenoid. The third circuit includes switches functionally identical to the switches for the foot brake locking mechanism release means, but in place of the switch that senses that the foot brake is locked, there is a switch that senses that the parking brake is on.

United States Patent Kimura [54] VEHICLE FOOT BRAKE LOCKING MECHANISM;FOOT BRAKE LOCKING MECHANISM RELEASE MEANS; AND PARKING BRAKE LOCKING 1MECHANISM RELEASE MEANS 72 Inventor: Seljl Kimura, 50s Seijo-Madhi,

Setagaya-ku, Tokyo 157, Japan [22] Filed: Feb. 9, 1970 [21] Appl. No.:9,524

[30] Foreign Application Priority Data Feb. 19, 1969 Japan ..44/011821May 12, 1969 Japan ..44/035715 [52] U.S.Cl. ..180/103, 188/140, 188/265,192/3, 303/20, 303/24, 303/89 [51] Int. Cl. ..'B60t 7/12 [58] Field ofSearch ..180/82, 103, 104; 188/110, 188/135, 140, 265; 192/3; 363/3, 20,24, 89;

Primary Examiner-Benjamin Hersh Assistant Examiner-John P. SilverstrimAttorney-Ostrolenk, Faber, Gerb & Soffen [5 7] ABSTRACT An electricalmechanism for locking the foot brake of a motor vehicle, including asolenoid which causesthe i551 Aug. I5, 1972 foot brake to be locked inposition and an electrical relay system comprises of a circuit which,when completed, actuates the solenoid; the relay system circuit includesthe vehicle ignition switch, a stop light switch which is closed whenthe foot brake is operated and the vehicle rear stop lights are lit; afirst switch which is closed when the automatic locking mechanism hasnot been activated; three second switches in electric parallel, a firstone that is associated with the gear shift lever and is closed when thegear shift lever is in Neutral gear, a second one that may be closed bythe vehicle operator if he desires the foot brake to automatically lock,and a third inertia controlled safety switch that is closed only afterthe vehicle has come to a full stop when there has been a rapiddeceleration of the vehicle. The foot brake locking mechanism releasemeans com- :prises a solenoid, which, when activated, causes release ofthe foot brake locking mechanism and a second relay system circuitassociated with this solenoid, which second circuit must be completed toactivate the solenoid; the second circuit includes the vehicle ignitionswitch, a second switch which is closed only when the gear shift leveris in one of the driving gears, a third switch which is closed when themotor is operating, a fourth switch which is closed only when the footbrake is locked, a fifth switch which is closed just as the vehicleoperator initiates movement of the vehicle, and in parallel with eachother there are a vacuum switch connected with the vehicle motorinduction manifold to be closed upon pressure reduction in this manifoldand a gravity controlled switch means which is closed when the vehicleis on a level surface and is open when the vehicle is facing uphill ordownhill. The parking brake locking mechanism release means alsocomprises a solenoid which, when actuated, releases the parking brakeand a third relay system circuit, which must be completed to activatethe solenoid. The third circuit includes switches functionally identicalto the switches for the foot brake locking mechanism release means, butin place of the switch that senses that the foot brake is locked, thereis a switch that senses that the parking brake is on.

30 Claims, 2 Drawing Figures VEHICLE FOOT BRAKE LOCKING MECHANISM; FOOTBRAKE LOCKING MECHANISM RELEASE MEANS; AND PARKING BRAKE LOCKINGMECHANISM RELEASE MEANS This invention relates to a motor vehicle footbrake locking mechanism and release means therefor and to a parkingbrake release means.

It is frequently desirable to lock the foot brake on a motor vehicle inthe depressed or applied position. For example, when an operator halts avehicle by depressing the foot brake pedal, he may find it uncomfortableor tiring to hold the brake pedal depressed for a prolonged period, suchas while the vehicle is standing at a railroad crossing. Should theoperator momentarily release the brake pedal, the vehicle might roll. Anautomobile with automatic transmission would creep forward if pressureon the brake pedal is relaxed. Furthermore, in the event, that onevehicle is struck by another, there is a danger that the driver of thestruck vehicle will be momentarily jolted into releasing the foot brakepedal. This could cause the struck vehicle to move into danger and couldcause whiplash injury to the driver. However, if the foot brake islocked when a vehicle comes to a halt, then even if the drivers foot isjolted off the foot brake pedal, the vehicle will not move.

A foot brake locking mechanism should operate (a) when the foot brakepedal is depressed and the vehicle is in Neutral gear, or (b) when thevehicle operator closes a switch to cause the foot brake lockingmechanism to operate as soon as the foot brake pedal is depressed, or(c) when the vehicle has been rapidly brought to a halt and there is adanger that the vehicle behind might strike the now halted vehicle.Accordingly, the foot brake locking mechanism of the present inventionwill operate when any of the above noted conditions occurs.

A vehicle parking (or hand or emergency) brake is manually appliedthrough a hand or foot operated lever. Conventionally, it is locked intopositionby a pawl and ratchet combination.

Automatic means may be provided for releasing either or both of thevehicle foot brake locking mechanism and the vehicle parking brake.Thus, when the vehicle operator wishes to move the vehicle, the brakeswill not impede movement. The automatic means, however, should bedesigned so as not to release either of the brakes when the vehicle ison an incline and is to move uphill until after the vehicle is ready tomove in the desired direction without rollback.

A parking brake is only occasionally applied, e.g. when the car isparked or expected to stand still for an extended period. Thus, it wouldnot be bothersome for the operator to have to manually release theparking brake. Here the release means of the invention is a convenience.

However, the foot brake pedal is frequently depressed. Were it to lockon every occasion, having to manually release the foot brake pedal eachtime would prove very annoying to the operator. He would avoid using theimportant safety advance provided by the foot brake locking mechanism.Thus, it is important here to provide an automatic release means.

For safety reasons, it is desirable that neither the parking nor thefoot brakes be released until the vehicle ignition switch is closed, thevehicle motor is operating, the motor is in one of the driving gears,the brake to be released is being applied and the means for initiatingmotion in the vehicle e.g. the accelerator pedal in automatictransmission vehicles is first operated; and, if the vehicle is on anincline, the operator has opened the throttle sufficiently to preventrollback as the vehicle starts. Only when all of these conditions aremet is it apparent that the operator of the vehicle desires it to move.Accordingly, the automatic foot brake and parking brake lockingmechanism release means of the present invention only release the footbrake and/or the parking brake when all the conditions are met. I

The foot brake locking mechanism of the present invcntion includes asolenoid device so connected with the vehicle brakes that when thesolenoid device is actuated, a check valve, which is selectivelypositionable between a one-way flow position. and a two-way flowposition, is caused to enter its one-way flow mode so that the hydraulicbrake fluid is caused only to lock the foot brake. The locking mechanismalso includes an electrical relay for actuating the solenoid device. Therelay is in a circuit which must be completed for the solenoid device tobe activated to lock the foot brake. The circuit includes the vehicleignition key switch; a vehicle stop light switch, the contacts of whichare closed when the brakes are applied; a first switch, the contacts ofwhich are closed when the foot brake locking mechanism has not beenactivated (this switch reduces unnecessary system deterioration, asdescribed in the detailed description below); and three alternativesecond switches connected in parallel, the first associated with thegear shift lever to be closed when that lever is in one of Neutral orPark gears, the second to be actuated by the operator of the vehicle ifhe desires the foot brake to automatically lock when the other switchesare closed, and the third inertia controlled switch that is closed uponthe vehicle coming to a full halt after rapid deceleration of thevehicle, such as would occur during an emergency stop. (The inertiacontrolled switch helps prevent chain collisions which occur when adriver, who has made an emergency stop, experiencing relief at havingavoided harm, releases the brake pedal and whose now lightly brakedvehicle is then struck by another vehicle which impels the struckvehicle into still another vehicle.) When the circuit is completed, thefoot brake locking solenoid device shifts the above described checkvalve to its one-way flow position.

The foot brake locking mechanism release means in cludes its ownsolenoid device, which, when activated, releases the foot brake lockingmechanism, and includes an electrical relay for actuating the solenoiddevice. The relay is in a circuit which must be completed before thesolenoid device will be activated to release the foot brake. The circuitincludes the vehicle ignition key switch, which is closed when theignition key is at the vehicle ON position; a second switch, which isclosed when the gear shift lever is in one of the vehicle driving gears;a third switch, which is connected to the vehicle motor through a relaydevice and which is closed only when the motor is operating; a

fourth switch, which is closed only when the foot brake has been locked(this switch prevents system deterioration, as described below in thedetailed description); a fifth switch associated with the means whichinitiates movement of the vehicle, the contacts of which are closed assoon as that means is activated to cause vehicle movement; and inparallel with each other there are, first, a vacuum switch connectedwith the vehicle motor induction manifold to be closed upon a pressurereduction in this manifold and, second, a gravity controlled switchmeans which is closed when the vehicle is on a level surface and is openwhen the vehicle is facing uphill or downhill. (The induction manifoldis the air conduit leading to the vehicle carburetor. The pressure inthat conduit is reduced when there is a load on the motor, which occurswhen the vehicle is about to accelerate and is accelerating and when thevehicle motor is retarding vehicle motion while the throttle is closed.)

The parking brake locking mechanism release means includes its ownsolenoid device which, when activated, releases the parking brake, andincludes an electrical relay for actuating the solenoid device. Therelay is in a circuit which must be completed before the solenoid devicewill be activated to release the parking brake. This circuit includesswitches functionally identical to those for the foot brake lockingmechanism release means, except that in place of the switch that sensesthat the foot brake is locked, there is a switch that senses that theparking brake is on.

Accordingly, it is a primary object of the present invention to providean effective vehicle automatic foot brake locking mechanism, a footbrake locking mechanism release means and a parking brake lockingmechanism release means.

It is a further object of the present invention to provide such lockingmechanisms and release means in combined form.

It is another object of the present invention to provide an effectivevehicle automatic foot brake locking mechanism.

It is another object of the present invention to provide an effectivevehicle automatic foot brake locking mechanism release means.

It is another object of the present invention to provide an effectivevehicle automatic parking brake locking mechanism release means.

It is a further object of the present invention to cause each of theforegoing mechanisms and means to operate without the operator of amotor vehicle being inconvenienced by having to manually operateextensive, extraordinary equipment.

It is still another object of the present invention to avoid having themovement of a vehicle noticeably af fected by the operation of thepresent invention.

It is a further object of the present invention to provide a mechanismfor locking the brakes of a vehicle by locking the foot brake when thevehicle is brought to a temporary halt.

It is yet another object of the present invention to provide a mechanismfor locking the brakes of a vehicle automatically when the vehicle isbrought to an emergency stop.

It is another object of the present invention to provide a means forreleasing the locking mechanism for the foot brake of a vehicle as soonas the driver indicates, by operating the means that initiates vehiclemovement while the motor is operating and the vehicle is in one of thedriving gears, that the driver wishes the vehicle to move. I

It is another object of the present invention to provide a release meansfor a vehicle parking brake to release the parking brake under the sameconditions as just described for the release of the foot brake.

It is yet a further object of the present invention to provide a meansfor releasing the locking mechanism of the foot brake and/or the parkingbrake of a vehicle when the vehicle is on an incline while preventingvehicle rollback.

It is still a further object of the present invention to provide avehicle foot brake locking mechanism, a foot brake locking mechanismrelease means and a parking brake locking mechanism release means, allof which use electric switching devices.

It is yet another object of the present invention to minimizedeterioration and unnecessary use of the apparatus of the invention.

These and other objects of the present invention will become apparentfrom the following description of the accompanying drawings in which:

FIG. 1 schematically illustrates a vehicle foot brake automatic lockingmechanism, a foot brake locking mechanism release means and a parkingbrake locking mechanism release means; and

FIG. 2 is a side cross-sectional view of the selective two-way-one-wayfluid switch of FIG. 1.

Each locking mechanism and release means will be described separatelyfor clarity. It is to be understood that a vehicle will contain all ofthe mechanisms described. Alternatively, it may contain only certain ofthe described mechanisms. The foot brake locking mechanism and therelease means therefor would usually be provided together since it wouldbe inconvenient to have a foot brake automatically lock, withoutautomatic means being provided for releasing the brake thereafter. Theparking brake release means need not be included with the foot brakelocking mechanism release means. However, since, as shown below, theparking brake release means and the foot brake locking mechanism releasemeans operate in a similar manner and may even share some components, itis sensible to include them in a single mechanism.

FOOT BRAKE LOCKING MECHANISM Turning to FIG. 1, the conventional footbrake pedal 10 is connected by conventional means 11 to the vehiclehydraulic brake master cylinders 12, 13. Master cylinders 12 and 13connect through respective conventional hydraulic fluid-carryingconduits 14a and 14b to conduit 14 and from there into a fluid switch 15which is adaptable to be selectively in either a two-way or a one-wayflow-through mode. As the former, the fluid switch permits the flow ofhydraulic fluid out of conduit 14 through switch 15 and into conduit 16,which leads to the four wheel brake cylinders to cause activation ofsame in the conventional manner; and the switch also permits flow in thereverse direction. As the latter, switch 15 only permits flow in thefirst described, but not in the reverse, direction. When the switch isin the latter mode, the brakes are adapted to be locked. When the brakesare applied, hydraulic fluid flows past switch in the first direction,but is blocked from returning to the master cylinders, thereby lockingthe brakes.

Referring to FIG. 2, fluid switch 15 includes a check valve 17interposed in the flow path between inlet conduit 14 and outlet conduit16. Spring 18 normally biases check valve 17 closed against itscooperating valve. seat 19. Thus, normally, only one-way flow ispermitted.

A vertically shiftable pusher is provided within conduit 16 beneathvalve 17. When pusher 20 moves into engagement with valve 17, it raisesthe valve off its seat 19 and permits free flow of hydraulic fluid pastnarrow pusher 20 in both directions. When pusher 20 is down away fromthe valve element 17, only one-way flow is permitted to the brakecylinders.

A cam 21 is selectively movable into and out of engagement with the endof pusher 20. In its simplest form, cam 21 merely consists of a circularpost with a cut-out, flattened section 22. When cam 21 is axiallyrotated so that the flattened section 22 faces pusher 20, the pusher isnot moving into engagement with valve 17, and one-way flow occurs. Whencam 21 is axially rotated so that its rounded portion engages pusher 20,the pusher is pressed into engagement with valve 17, opens the valve,and permits two-way flow.

Cam 21 is connected, by a support post 23 which is appropriately sealedby a fluid-tight bearing, to the pivotable lever. 25.

Lever 25 is connected to the plunger 26 of a conventional solenoid 24.When solenoid 24 is activated, it draws plunger 26 to the right, asviewed in FIG. 1. This pivots lever 25 clockwise to its phantom lineposition, which, in turn, rotates cam 21 clockwise, as viewed in FIG. 1.This causes flattened cam section 22 to come opposite pusher 20, therebypermitting locking of brake pedal 10 in the manner described above. Asdescribed further below, when brake pedal 10 is to be released, lever 25is shifted counterclockwise to its solid line position of FIG. 1, whichbrings the rounded portion of cam 21 into engagement with pusher 20,thereby causing the pusher to raise valve 17 and permit free, two-wayhydraulic fluid flow.

An over-center spring 27 is connected with lever 25 to rapidly move itbetween its two positions and to securely hold it in each position.

The electrical circuit for causing operation of solenoid 24 leads fromground connection 28; through solenoid 24; lead 30; relay switch 32,whose contacts 34, normally open, are closed by relay coil 36, to befurther described below; leads 38, 40; power supply 42; to groundconnection 44. Once contacts 34 of relay switch 32 are closed, solenoid24 is automatically activated and the automatic foot brake lockingmechanism operates.

When coil 36 is activated, the magnetic attraction closes the normallyopen contacts 34. Coil 36 is activated when the circuit within which itis located is completed. This circuit leads from ground connection 46;through coil 36; lead 50; switch 52; lead 54; one or more of switches55, 56 and 58, which are arranged in electrical parallel to each otherin the circuit; lead 60; brake light switch 62; leads 64 and 66;ignition key switch 68; leads 70; 72; 74; power supply 42; to groundconnection 44. The switches just mentioned will be described in reverseorder.

Ignition key switch 68 is conventional and its contacts are closed whenignition key 76 is turned to the vehicle motor ON position.

Conventional vehicle stop light switch 62 is closed when the foot brakesare applied. Conduit 16 has a branch 63a which is connected to stoplight switch 62. Elevated hydraulic pressure in conduit 16 due to thebrakes being applied closes the contacts to switch 62 and causes thevehicle stop lights to light up. To prevent the stop lights being lefton after the vehicle has been parked with the foot brake locked, switch62 is in circuit with the ignition switch 68. As soon as the ignitionswitch is turned off, power to the stop lights is also cut off.

Switches 55, 56 and 58 are in electrical parallel. Closing of any ofthese switches will permit the circuit to be completed.

Gear shift lever switch 58 is a conventional electric switch whosecontacts are closed when the gear shift lever 59 is placed in one of thenon-drive gears, e.g. Neutral or Park.

The contacts of manual switch 56 are engaged by the operator of thevehicle moving the conventional operating arm of the switch 56 to thecontacts engaged position. With switch 56 in this position, every timethe other switches in the relay switch operating circuit are closed, thebrakes are locked.

Switch is inertia controlled. Its contacts, schematically illustrated as57a and 57b, are normally open and are closed by the inertia forceexerted on the switch by acceleration of the vehicle (which isirrelevant to the brake applying means since that means only operateswhen the brake is applied) and by the reaction return to stable positionwhich the vehicle undergoes upon stopping after having rapidlydecelerated. Usually, in rapid deceleration, the vehicle tilts forward.Upon halting, the vehicle reacts by swinging back to its stableposition. Switch 55 is a conventional mercury switch with the fixedcontact so placed that rapid vehicle deceleration moves the liquidmercury away from the fixed contact. The liquid shifts into contact withthe fixed contact to complete the circuit, once the vehicle has haltedcompletely and has reacted to the deceleration by restabilizing itself.While switch 55 is closed only immediately after the vehicle halts, solong as the circuit which activates coil 36 is even momentarilycompleted, this is enough to activate solenoid 24 and shift switch 15 toits one-way flow, brakes locked mode.

Conventional switch 52 is engaged by lever 25 after locking position.Switch 52 includes contacts which are normally engaged so as to completethe electric circuit to the relay that causes operation of solenoid 24and which are separated by the shifting of lever 25 into engagement withthe operator for switch 52. Thus, prior to shifting of lever 25 to thebrake locking position, the contacts of switch 52 are engaged. As soonas the shift occurs and switch 15 has been shifted so that the brakesare locked, the circuit that causes activation of solenoid 24 is broken,whereby power will not be wasted through constant energization ofsolenoid 24, and the solenoid will not be burned out through longcontinued and unnecessary activation.

Through the solenoid activating circuit just described, the foot brakelocking mechanism operates only when the operator is driving thevehicle, has depressed the foot brake pedal, and has (a) manually closedswitch 56, or (b) placed the vehicle in a nondriving gear or (c) haltedthe vehicle after rapidly decelerating it. When the motor is off and theignition key switch 68 is off, the solenoid activating circuit isincomplete. The contacts of switch 52 are engaged when lever 25 is inits solid line position before it shifts to its phantom line position.One of switches 56 or 58 is closed, as described above. The brake pedalis depressed closing the contacts of switch 62. Now that the circuit torelay switch coil 36 is completed, relay switch contacts 34 move intoengagement, solenoid 24 is activated, and since pedal 10 is depressed,the foot brake will be locked.

FOOT BRAKE LOCKING MECHANISM RELEASE MEANS As noted above, after thefoot brake has been locked, when it is necessary to move the vehicleagain, it is desirable to automatically release the locked foot brake.

Turning to FIG. 1, to release the foot brake locking mechanism, switchmust be shifted counterclockwise to its solid line position whichpermits free, two-way flow through the switch, as described above,rather than mere one-way flow away from master cylinders 12, 13.Hydraulic fluid can now flow back from the wheel cylinders to the mastercylinders. The springs in the conventional vehicle wheel brake drums(not shown) retract the brake shoes in a conventional manner andinstantly release the brakes. Lever 25, as noted above, is connectedwith plunger 26, which also serves as the plunger for solenoid 152.Thus, activation of solenoid 152 draws plunger 26 counterclockwise andcauses release of the foot brake, as just described.

Solenoid 152 is in an electrical circuit which must be completed beforethe solenoid is activated. The circuit extends from ground connection156; through solenoid 152; lead 158; relay switch 160, whose contacts162 are closed when coil 164 is activated as described below; leads 166;40; power supply 42; to ground connection 44. From the foregoing, it isapparent that when contacts 162 are engaged, due to activation of coil164, solenoid 152 is activated.

Coil 164 is in an electrical circuit extending from ground connection168; through motor condition sensing relay switch 170, which includescontacts 80, to be further describedbelow; lead 174; switch 176 forsensing when lever 15 is in the position to lock the foot brakes; lead178; vehicle motion initiating means sensing switch 180; lead 181;optional inclined surface rollback prevention switch means 182; lead183; gear shift lever position sensing switch 184; lead 66; ignition keyswitch 68; leads 70; 72; 74; power supply 42; to ground connection 44.

Considering the switches in the circuit of coil 164 in reverse order,the ignition key switch 68, as previously described, includes contactswhich close only when the ignition key is in the ON position. Gear shiftlever switch 184 includes contacts which are closed only when the gearshift lever is in one of the driving gears, thus showing that the driverwishes the vehicle to move.

Inclined surface rollback prevention switch means 182 is optional. If itis not included, leads 181 and 183 merely merge. Switch means 182includes a gravity controlled switch means 302 in electrical parallelwith a vacuum switch 304 which is connected, through conduit 306, with aconventional vehicle induction manifold (not shown). When the vehicle ison a level surface, switch means 302 is always closed and the circuitthrough switch means 182 is always complete.

When the vehicle is on an inclined surface and is to be started in theuphill direction, as will be described below, switch means 302 willalways be open. When a load is placed on the vehicle motor by causingthe vehicle to pull uphill against the now engaged foot brake, contacts305a and b of vacuum switch 304 close, and the circuit through switchmeans 182 is complete. Thus, switch means 182 is not closed until thevehicle motor is driving the vehicle uphill with sufficient force toprevent rollback.

On the other hand, switch means 302 is so designed that when the vehicleon the incline is to be started in the downhill direction, switch means302 is always closed so that the circuit through switch means 182 iscomplete and there is no need to wait for a pressure decrease in theinduction manifold to release the foot brake.

The key to the foregoing operation lies in gravity controlled switchmeans 302. This is comprised of gear shift lever position responsiveswitch 308 and gravity responsive shifts 312 and 316.

Switch 308 includes switch arm 309 which is electrically connected withlead 183 and is mechanically operated, through conventional means 307,by gear shift lever 59. When lever 59 is in a vehicle forward motiongear, e.g. Drive or Low, contact arm 309 closes the circuit to contact310, which leads into switch 312. When lever 59 is in a vehicle rearwardmotion gear, e.g. Reverse, contact am 309 closes the circuit to contact31 1, which leads into switch 316.

Switch 312 is a gravity controlled switch whose contact element 313 isout of circuit with contact arm 309, when the vehicle is facing uphillon an incline and whose contact element 313 is in circuit with contactarm 309, as illustrated in FIG. 1, when the vehicle is on a levelsurface or is facing downhill. Contact element 313 leads into circuitlead 181.

When the vehicle is on a level surface or is facing downhill and thevehicle gear shift lever is in a forward motion gear so that arm 309 isin circuit with switch 312, (as illustrated in FIG. 1,) the circuit fromlead 183 passes through contact arm 309 and contact element 313 to lead181, and there would be no delay in release of the foot brake such asmight arise from awaiting operation of vacuum switch 304. But, when thevehicle is on an incline and is to move forward uphill, contact element313 breaks the circuit with switch arm 309.

The only way to complete the circuit through switch means 182 is forvacuum switch 304 to be operated by a load being placed on the motor, asdescribed above. In this manner, rollback is prevented.

Gravity controlled switch 312 is a conventional liquid mercury switchwith contact element 313 being the liquid mercury, and the contactswithin the switch being arranged so that the mercury moves away from thecontact leading to switch arm 309 when the vehicle is facing uphill.

Switch 316 is a similar gravity controlled switch to switch 312. Contactelement 317 here is out of circuit with contact arm 309 (as illustratedin FIG. 1,) when the vehicle is facing downhill on an incline and is incircuit with contact arm 309 when the vehicle is on a level surface oris facing uphill. Contact element 317 leads into circuit lead 181.

When the vehicle is on a level surface or is facing uphill and thevehicle gear shift lever is in a reverse direction motion gear so thatarm 309 is in circuit with switch 316, the circuit from lead 183 passesthrough contact arm 309 and contact element 317 to lead 181. There wouldbe no delay in release of the foot brake such as might arise fromawaiting operation of vacuum switch 304. But, when the vehicle is on anincline and is to move backward uphill, contact element 317 breaks thecircuit with switch arm 309. The only way to complete the circuitthrough switch means 182 is for vacuum switch 304 to be operated by aload being placed on' the motor, as described above. In this manner,rollback is prevented.

Gravity controlled switch 316 is also a conventional mercury switch withcontact element 317 being the liquid mercury, and the contacts withinthe switch being arranged so that the mercury moves away from thecontact leading to switch arm 309 when the vehicle is facing downhill.

Vehicle motion initiating means sensing switch 180 includes contactswhich are closed when the vehicle motion initiating means is firstoperated to initiate vehicle movement. In FIG. 1, this means comprisesvehicle accelerator pedal 185, and when pedal 185 just starts to movedown, the contacts of switch 180 are closed, so that when the otherswitches are closed, the circuit to coil 164 is complete and brakerelease occurs, and all this before the vehicle begins to move, as nowdescribed. Pedal 185 is normally held up by spring 186. This causes agap 187 between pedal 185 and throttle rod 188. Thus, before theaccelerator pedal touches the throttle rod to initiate vehicle movement,the pedal has moved away from switch 180 to open the contacts thereof,so that the brake could be released just before vehicle movementcommences.

The above discussed gap 187 also permits independent motion of throttlerod 188. Should a mechanic or other individual manually open the vehiclethrottle under the vehicle hood, for example, although throttle rod 188might move, the spring supported accelerator pedal 185, and thus switch180, will not be affected, and the locked brakes will not be released.Also, when the automatic choke on the vehicle carburetor is operator tothe motors fast idling speed, before the motor warms up, although theposition of the throttle rod might be affected, the position of theaccelerator pedal is not affected and there is no undesired release ofthe brake locking mechanism. Thus, gap 187 ensures that the lockedbrakes will not be released until the vehicle operator depresses theaccelerator pedal indicating his desire that the vehicle move.

Relay switch 80 senses whether the automobile motor is operating. Thecontacts 80 of the switch are normally biased into engagement. When anelectric current flows through coil 82, contacts 80 are drawn apart.Leads 84 and 86, which bring current to coil 82, are, respectively,connected to leads 88 and 90. Leads 88 and 90 are connected into theconventional motor vehicle voltage regulator 92 and into theconventional vehicle alternator 94. Since these items are conventionalin motor vehicles, they will not be described in detail. Tracing thecurrent path from lead 90 to lead 88, the path is from lead 90; throughleads 93; 96, 98; relay switch 100; lead 102 in switch 100; thencontacts 104, which are normally biased closed, but which are caused tobe opened due to activation, as described below, of coil 106; lead 108;to lead 88. Lead 98 which passes into switch 100 also connects withground connection 110. Leads 88 and 90 also merge into lead 112 which,in turn, connects through ignition key switch 68; leads 72; 74; to powersupply 42; and then to ground connection 44. Separation of contacts 104in switch 100 due to activation of coil 106 breaks the circuit whichincludes leads 88 and and thereby breaks 7 the circuit to coil 82 as themotor runs.

Coil 106 is electrically connected through lead 114 with conventionalrotating armature 116 of conventional vehicle alternator 94. Whenarmature 116 rotates, due to therotation of conventional automobilemotor (not shown), in the field of conventional field coil 118, thecurrent generated in armature 116, through lead 114, activates coil 106.This draws apart the normally engaged contacts 104. Thus, as soon as thevehicle motor is operating, the circuit, which in cludes contacts 104,that charges coil 82 in switch 48 is broken, and contacts 80 resumetheir normally engaged position.

Contacts 80 are normally engaged. When ignition key 76 is turned to theoperative position, thereby closing switch 68, the circuit to coil 82through relay switch is activated, and contacts 80 are separated. Thus,

although the ignition key switch is: on, because the vehicle motor isnot operating, the circuit to relay switch coil '164 is not complete.When the vehicle motor is finally operating and the armature 116 isrotating, switch contacts 104 are disengaged, coil 82 is deenergized andcontacts 80 are reengaged, thereby permitting the circuit to coil 164 tobe completed.

Thus, for the foot brake locking mechanism to be released, it isnecessary that the operator of the vehicle evince his desire for thevehicle to move by turning on the ignition switch, starting the motor,placing the gear shift lever in a drive gear, and depressing theaccelerator pedal. If the rollback prevention device is included and thevehicle is to move uphill, it is also necessary that the acceleratorpedal be sufficiently depressed to place a load on the motor. As soon asthe driver does all these things, the vehicle is about to move, thecircuit to coil 164 is completed, solenoid 152 is activated and lever 15shifts counterclockwise to its solid line position, thereby raisingvalve element 17, as described above, so that fluid can return to themaster cylinders, and thereby releasing the brake locking mechanism.With the release means described, the vehicle motor will not have tomove the vehicle against the drag provided by the foot brake. Because itis not necessary for the operator of a vehicle to remember to releasethe foot brake locking mechanism, he may be inclined to use the footbrake pedal locking mechanism, described above, which is a safety devicein the vehicle.

As with the foot brake locking mechanism, the release means therefor isimmediately deactivated as PARKING BRAKE RELEASE MEANS Most motorvehicles are provided with a manually operable parking brake that isseparate from the foot brake. Turning to FIG. 1, parking brake 200includes a shaft 202 which is connected by conventional means (notshown) with brake shoes (not shown) of a vehicle. When the parking brakeshaft 202 is pulled outward, or

to the right, as viewed in FIG. 1, by handle 203 to its phantom lineposition, the parking brake is engaged. A spring biasing means 204normally attempts to return shaft 202 to the parking brake releaseposition. Shaft 202 is, therefore, provided with a set of ratchet teeth206 which are engaged by pawl 208 when the shaft 202 has been shifted tothe parking brake engaged position. Pawl 208 is normally biased intosecure engagement with ratchet teeth to prevent release of the brake.The parking brake may be conventionally released through, for example,rotation of handle 203 which rotates the ratchet teeth away from thepawl 208, permitting mechanical release of the parking brake.

Some conventionally employed parking brakes use a pivotable, depressiblefoot pedal, rather than a pull handle, like 203. These other types ofbrakes do employ a pawl and ratchet locking arrangement like 206, 208,or a similar locking arrangement, which may be released in accordancewith the teachings herein.

The present invention is particularly directed to an automatic means forreleasing the parking brake. In accordance with the invention, pawl 208is secured to or is part of the plunger of solenoid 212. When solenoid212 is activated, by means to be described, pawl 208 is retracted fromengagement with ratchet teeth 206, and parking brake shaft 202 ispermitted to shift to the left under the influence of biasing means 204,thereby releasing the parking brake.

Solenoid 212 is activated through completion of the circuit extendingfrom ground connection 214; through relay switch 216, whose contacts218, normally disengaged, are engaged by activation of relay coil 220,as further described below; leads 221; 72; 74; power supply 42; toground connection 44. When contacts 218 are engaged, the circuit tosolenoid 212 is completed.

To cause the engagement of contacts 218 of relay switch 216 requires thecompletion of the circuit in which relay coil 220 is connected. Theparking brake should be released under the same conditions as the footbrake. Accordingly, the switches in the circuit in which coil 220 isconnected for releasing the parking brake in most cases are the same asthe switches as in the circuit to coil 164 to releasing the foot brake,and in the remaining cases are functionally identical to those used forreleasing the foot brake.

The circuit which must be completed to activate coil 220 extends fromground connection 222, through motor condition sensing relay switch 224whose contacts 226 must be in engagement before the circuit iscompleted; lead 227; switch 228, which senses when the parking brake hasalready been applied, and, therefore, should be released; lead 229;accelerator pedal position sensing switch 180; lead 181; optionalrollback prevention switch 182; gear shift lever position sensing switch184; lead 66; ignition key switch 68; leads 70; 72; and 74; power supply42; to ground connection 44.

Considering the switches just mentioned in reverse order, switches 68,184, 182 and 180 have previously been discussed. Switch 228 isfunctionally analogous to switch 176, previously discussed. Switch 228has its contacts closed when the switch is engaged by a switch operator230 on shaft 202 of the parking brake. Operator 230 contacts switch 228only when shaft 202 is drawn to the right and the parking brake is on.Motor condition sensing relay 224 is identical to the previouslydescribed motor condition sensing relay 170. Its coil 232 is connectedbetween leads 88, 90 whereby relay 224 acts in the same way as relay170.

When the operator of the vehicle turns on the ignition switch, startsthe motor and the motor is operating, places the vehicle in one of thedriving gears, and first touches the accelerator pedal, while theparking brake is on, all of the switches'in the circuit to coil 220 areclosed, and the coil is activated. Of course, if rollback preventionswitch 182 is included, the circuit to coil 220 is not completed until aload is placed on the motor. The circuit to solenoid 212 is therebycompleted, causing the parking brake 220 to be released beforecommencement of movement of the vehicle. Again the brake is releasedbefore the vehicle commences movement due to gap 187 and on a hill, dueto switch 182, as described above.

As with the foot brake locking mechanism release means, as soon as theparking brake is released, the contacts of switch 228 are opened, sincethe switch operator 230 is no longer in engagement with the switch, andthe circuit to coil 220 is broken, thereby deactivating the coil anddeactivating the solenoid 212. This prevents power from continuouslybeing drawn by solenoid 212 and protects the solenoid from being burnedout through unnecessary continuous activation.

There has just been described a vehicle foot brake locking mechanism andfoot and parking brake locking mechanism release means, which includesan electric switching apparatus to cause the foot brake of a vehicle tobe locked when the operator of the vehicle wishes and combines withthis, a release means for the foot brake locking mechanism and a releasemeans for the parking brake of the vehicle, both of which release meansoperate when the vehicle motor is running, the vehicle is in one of thedriving gears, and means which initiates movement of the vehicle isabout to begin to initiate such movement while the brake still remainsengaged.

1. In a movable vehicle having foot brakes operated by a foot brakepedal, a foot brake locking mechanism for locking the foot brakes in thebrakes applied position;

a second switch mechanically connected with said locking mechanism andhaving contacts which are mechanically engaged by said locking mechanismwhen said locking mechanism is activated and said locking mechanismincluding an electrically which are separated by said locking mechanismoperable mechanism for locking said brakes; said when said lockingmechanism is deactivated; electrically operable mechanism beingconnected a first motor condition sensing switch, the contacts of to apower source by means of a first electric cirwhich are normally engagedand are responsive l0 cuit, which first circuit must be completed beforeI 0' activation of a first y; 3 st relay associated said electricallyoperable mechanism will cause with and Positioned to act p Said contactsof id f t b ak to lock; said first motor condition sensing switch tocause said first circuit includingaplurality of switches, with same to pte en the vehicle motor is off each switch including cooperatingcontacts, which whiie Said ignition y Switch is at the P cooperatingcontacts of each switch must be en- 15 tion and 9 Cause Same to reehgagewhen the Vehigaged to complete said first circuit; said switches ciehiotor also on; are: vehicle movement initiating means switch conanignition key switch, the contacts of which are enhe with the means inVehieie which gaged When Said vehicle ignition key is at the vehiltiates movement of the vehicle, which switch has ole position and areseparated When said contacts that are normally dlsengaged and which keyis at other than the vehicle ON position; I are engaged y Operation ofthe Vehicle a switch connected with said vehicle gear shift leverinitiating means in a manner which will initiate and having its contactsarranged so that they are vehicle movemfmti engaged when said gear shiftlever is shifted into a whefeby when P fontacts of all of i Switches ofvehicle nomdriving gear and separated when said said second circuit areengaged, said foot brake gear shift lever is shifted into a vehicledriving gear;

pedal locking mechanism release means is activated to release said brakepedal from said locking mechanism.

2. In the movable vehicle having foot brakes and a foot brake lockingmechanism release means of claim said vehicle motion initiating meanscomprising an accelerator pedal that is adapted to move into engagementwith and to then operate a rod connected with the vehicle throttle,which rod, when operated, causes throttle operation;

means for supporting said accelerator pedal a predetermined distanceaway from said throttle rod;

said vehicle movement initiating means switch being positioned to engagesaid accelerator pedal when that said pedal is held away from saidthrottle rod; that said switch being so positioned that as soon as aswitch responsive to the position of the brake pedal, the contacts ofwhich are closed when the brake pedal is depressed;

a switch mechanically connected with said locking mechanism and havingcontacts which are caused to be mechanically engaged by said lockingmechanism when said locking mechanism is de-ac- 3 5 tivated and whichare caused to be disengaged by said locking mechanism when said lockingmechanism is activated, whereby once said locking mechanism isactivated, said contacts of that said switch separate and said firstelectric circuit is broken, thereby preventing unneeded power loss andpremature deterioration of said electrically operable mechanism;

whereby when said contacts of all of said switches I I said acceleratorpedal is moved toward said throtare engaged Said lockmg mechanismafmvatefi tle rod, the contacts of that said switch are caused to locksaid brake pedal III the brakes applied posito be engaged.

tion; 3. In the movable vehicle having foot brakes and a a foot brakelocking mechanism release means foot brake locking mechanism releasemeans of claim eluding a second electrically operable mechanism; 1

said second electrically operable mechanism being connected to a powersource by means of a second electric circuit, which second circuit mustbe completed before said second electrically operable mechanism willcause release of said foot brake locking mechanism;

said second circuit including a plurality of switches, with each switchhaving cooperating contacts which must be engaged to complete saidsecond circuit; said second circuit switches including:

said ignition key switch;

a second gear shift lever switch connected with said gear shift leverand having its contacts arranged so that they are engaged when said gearshift lever is shifted into a vehicle driving gear and separated whensaid gear shift lever is shifted into a vehicle non-driving gear;

said second circuit further including an uphill travel rollbackprevention switch means comprising, in electrical parallel: a gravitycontrolled switch means the contacts of which are adapted to be engagedwhen the vehicle is on a level surface and when the vehicle is to movedownhill on an incline and the contacts of which are adapted to bedisengaged when the vehicle is to move uphill, and a vacuum switchconnected to the vehicle induction manifold and whose contacts areadapted to be engaged upon a reduction of pressure in the inductionmanifoldl 4. In the movable vehicle having foot brakes and a foot brakelocking mechanism release means of claim 1, said vehicle having aparking brake which is applied by manual means by the vehicle operator,a locking mechanism for holding said parking brake in the appliedposition after it has been manually applied, and a parking brake lockingmechanism release means;

said parking brake locking mechanism including a holding device forengaging and holding said parking brake in the applied position;

said parking brake locking mechanism release means including a thirdelectrically operable mechanism for releasing said parking brake fromsaid second holding device; said third electrically operable mechanismbeing connected to a power source by means of a third electric circuit,which third circuit must be completed before said third electricallyoperable mechanism will cause release of said parking brake;

said third circuit including a plurality of switches, with each switchhaving cooperating contacts which must be engaged to complete said thirdcircuit; said third circuit switches including:

said ignition key switch;

said second gear shift lever switch;

a third switch mechanically connected with said parking brake and havingcontacts which are mechanically engaged by said parking brake when saidparking brake is locked in the applied position and which are separatedby said parking brake when said parking brake is released from theapplied position;

a second motor condition sensing switch, the contacts. of which arenormally engaged and are responsive to activation of a second relay; asecond relay associated with and positioned to act upon said contacts ofsaid second motor condition sensing switch to cause same to separatewhen the vehicle motor is off while said ignition key switch is at theON position and to cause same to reengage when the vehicle motor is alsoon;

said vehicle motion initiating means switch;

whereby when said contacts of all of said switches of said third circuitare engaged, said parking brake locking mechanism is released to releasesaid parking brake from the applied position.

5. In the movable vehicle having parking brakes and a parking brakelocking mechanism release means of claim 4,

said third circuit further including an uphill travel rollbackprevention switch means comprising, in electrical parallel; a gravitycontrolled switch means the contacts of which areadapted to be engagedwhen the vehicle is on a level surface and when the vehicle is to movedownhill on an incline and the contacts of which are adapted to bedisengaged when the vehicle is to move uphill, and a vacuum switchconnected to the vehicle induction manifold and whose contacts areadapted to be engaged upon a reduction of pressure in the inductionmanifold.

6. In the movable vehicle having parking brakes and a parking brakelocking mechanism release means of claim 4,

said vehicle motion initiating means comprising an accelerator pedalthat is adapted to move into engagement with and to then operate a rodconnected with the vehicle throttle, which rod, when operated, causesthrottle operation;

means for supporting said accelerator pedal a predetermined distanceaway from said throttle rod;

said vehicle movement initiating means switch being positioned to engagesaid accelerator pedal when that said pedal is away from said throttlerod; that said switch being so positioned that as soon as saidaccelerator pedal is moved toward said throttle rod, the contacts ofthat said switch are caused to be engaged.

7. In the movable vehicle having brakes of claim 1, said first circuitfurther including a manually operable switch, the contacts of which areengageable and separable by the vehicle operator; said manually operableswitch being connected in electrical parallel to said switch connectedwith said vehicle gear shift lever.

8. In the movable vehicle having brakes of claim 1, said first circuitfurther including an inertia controlled switch the contacts of which areclosed upon the vehicle halting after undergoing rapid deceleration.

9. In the movable vehicle having brakes of claim 8, wherein said inertiacontrolled switch is a mercury switch the fixed contact of which ispositioned to be contacted by the liquid mercury contact on the reactionmotion of the vehicle when it is halted after rapid deceleration.

10. In the movable vehicle having brakes of claim 8, said first circuitfurther including a manually operable switch, the contacts of which areengageable and separable by the vehicle operator; said manually operableswitch being connectedin electrical parallel to said switch connectedwith said vehicle gear shift lever.

1 1. In the movable vehicle having brakes of claim 1, said electricallyoperable mechanism comprising a solenoid device having a plungerconnected to said locking mechanism and being positioned to causeactivation of said locking mechanism when said first circuit, which isconnected to operate upon said solenoid device, is completed.

12. In the movable vehicle having brakes of claim 1 1, said solenoiddevice being connected to said power supply through the contacts of afirst relay; said contacts of said first relay being normally separated;said first relay being connected with said first electric circuit suchthat when said first electric circuit is completed, said contacts ofsaid first relay are engaged and the circuit to said solenoid device iscompleted.

13. In the movable vehicle having brakes of claim 1 1, said foot brakepedal being connected to a master cylinder hydraulic fluid source andsaid fluid source being connected to the vehicle brakes, wherebydepressing said foot brake pedal transmits fluid pressure to the vehiclebrakes to brake the vehicle;

said locking mechanism further comprising a flow switch interposedbetween said brake pedal and the vehicle brakes, which switch isselectively adjustable between a first position which permits one-wayflow away from said brake pedal, thereby only permitting said brakepedal to be depressed and the brakes to be applied, and a secondposition which permits two-way flow both away from and back towards saidbrake pedal;

said solenoid device plunger being connected with said switch to causesame to shift to its said first position when said solenoid device isactivated.

14. In the movable vehicle having foot brakes operated by a foot pedalof claim 13, said foot brake locking mechanism release means;

being connected with said flow switch in a manner such that when saidrelease means is activated, it

causes said flow switch to shift to its said second position.

15. In a movable vehicle having foot brakes operated by a foot pedal, afoot brake locking mechanism; and a foot brake locking mechanism releasemeans;

said release means including an electrically operable mechanism forreleasing said foot brakes from said locking mechanism; saidelectrically operable mechanism being connected to a power source bymeans of a first electric circuit, which first circuit must be completedbefore said electrically operable mechanism will cause release of saidbrakes;

said first circuit including a plurality of switches, with each switchhaving cooperating contacts which must be engaged to complete said firstcircuit; said switches including:

an ignition key switch, the contacts of which are engaged when thevehicle ignition key is at the vehicle ON position and are disengagedwhen said key is at other than the vehicle ON position;

a gear shift lever switch connected with said gear shift lever andhaving its contacts arranged so that they are engaged when said gearshift lever is shifted into a vehicle driving gear and separated whensaid gear shift lever is shifted into a vehicle non-driving gear;

a motor condition sensing switch, the contacts of which are normallyengaged and are responsive to activation of a first relay; a first relayassociated with and positioned to act upon said contacts of said motorcondition sensing switch to cause same to separate when the vehiclemotor is off while said ignition key switch is at the vehicle ON"position and to cause same to reengage when the vehicle motor is alsoon;

a switch mechanically connected with said locking mechanism and havingcontacts which are mechanically engaged by said locking mechanism whensaid locking mechanism is activated and which are separated by saidlocking mechanism when said locking mechanism is deactivated; wherebyonce said locking mechanism is released under the influence of saidelectrically operable mechanism, said contacts of said switch that ismechanically connected with said locking mechanism separate and saidfirst electric circuit is broken, thereby preventing unneeded power lossand premature deterioration of said electrically operable mechanism;

a vehicle movement initiating means switch connected with the means inthe vehicle which initiates movement of the vehicle, which switch hascontacts that are normally disengaged and which are engaged by operationof the vehicle movement initiating means in a manner which will initiatevehicle movement;

whereby when said contacts of all of said switches of said first circuitare engaged, said foot brake pedal locking mechanism release means isactivated to release said brake pedal from said locking mechanism.

16. [n the movable vehicle having foot brakes and a foot brake lockingmechanism release means of claim 15,

said first circuit further including an uphill travel rollbackprevention switch means comprising, in electrical parallel; a gravitycontrolled switch means the contacts of which are adapted to be engagedwhen the vehicle is on a level surface and when the vehicle is to movedownhill on an incline and the contacts of which are adapted to bedisengaged when the vehicle is to move uphill, and a vacuum switchconnected to the vehicle induction manifold and whose contacts areadapted to be engaged upon a reduction of pressure in the inductionmanifold.

17. In the movable vehicle having foot brakes and a foot brake lockingmechanism release means of claim 15,

said first circuit including a gravity controlled switch means; saidgravity controlledl switch means comprising:

a gear shift lever position responsive switch adapted to be selectivelyengageable with one of two gravity controlled switch devices which areconnected in electrical parallel;

said gear shift lever switch being connected with a first gravitycontrolled switch device when the gear shift lever is in one of theforward motion gears, and being connected with the second such switchdevice when the gear shift lever is in a rearward motion gear;

said first gravity controlled switch having its contacts so arrangedthat they are disengaged when the vehicle is facing uphill and engagedwhen the vehicle is on a level surface and when it is facing downhill;

said second gravity controlled switch having its contacts so arrangedthat they are disengaged when the vehicle is facing uphill and engagedwhen the vehicle is on a level surface and when it is facing uphill.

18. In the movable vehicle having foot brakes and a foot brake lockingmechanism release means of claim 17,

both said first and said second gravity controlled switch devices beingmercury switches with the fixed contact being positioned to be contactedby the movable mercury contact when the vehicle is respectively facingother than uphill and other than downhill.

19. In the movable vehicle having foot brakes and a foot brake lockingmechanism release means of claim 15,

said vehicle motion initiating means comprising an accelerator pedalthat is adapted to move into engagement with and to then operate a rodconnected with the vehicle throttle, which rod, when operated, causesthrottle operation;

means for supporting said accelerator pedal a predetermined distanceaway from said throttle rod;

said vehicle movement initiating means switch being positioned to engagesaid accelerator pedal when that said pedal is held away from saidthrottle rod; that said switch being so positioned that as soon as saidaccelerator pedal is moved toward said throttle rod, the contacts ofthat said switch are caused to be engaged.

20. In the movable vehicle having foot brakes, a foot brake lockingmechanism and a release means for said locking mechanism of claim 15,

said electrically operable mechanism comprising a solenoid device havinga plunger connected to said brake locking mechanism and being positionedto move said locking mechanism away from said brakes applied positionwhen said first circuit, which is connected to operate upon saidsolenoid device, is completed.

21. In the movable vehicle having foot brakes, a foot brake pedallocking mechanism and a release means for said locking mechanism ofclaim 15,

a second relay which is connected through a second electric circuit tosaid first relay; said second relay having contacts, which, whenengaged, complete the second circuit to said first relay, and which,when separated, break said second circuitto said first relay;

a power supply connected to said first relay through a third electriccircuit including said second relay and said ignition key switch; whensaid contacts of said ignition key switch are engaged and said contactsof said second relay are engaged, said second circuit is completed andsaid first relay is activated and said contacts of said motor conditionsensing switch are separated;

said second relay being connected with the motor of said vehicle suchthat when said motor is operating, said contacts of said second relayare separated and said second circuit to said first relay is brokenthereby deactivating said first relay, which, in turn, permits saidcontacts of said motor condition sensing switch to be normally biasedinto engagement, which permits said first electric circuit of saidelectrically operable mechanism to be completed.

22. In the movable vehicle having foot brakes, a foot brake lockingmechanism and a release means for said locking mechanism of claim 21,

said solenoid device being connected to said power supply through thecontacts of a third relay; said contacts of said third relay beingnormally separated; said third relay being connected with said firstelectric circuit such that when said first electric circuit iscompleted, said contacts of said third relay are engaged and the circuitto said solenoid device is completed.

23. In a movable vehicle having a parking brake which is applied bymanual means by the vehicle operator, a locking mechanism for holdingsaid parking brake in the applied position after it has been manuallyapplied, and a parking brake locking mechanism release means;

said parking brake locking mechanism including a holding device forengaging and holding said parking brake in the applied position;

said release means including an electrically operable mechanism forreleasing said parking brake from said holding device; said electricallyoperable mechanism being connected to a power source by means of a firstelectric circuit, which first circuit must be completed before saidelectrically operable mechanism will cause release of said parkingbrake;

said first circuit including a plurality of switches, with each switchhaving cooperating contacts which must be engaged to complete said firstcircuit; said switches including:

an ignition key switch, the contacts of which are engaged when saidvehicle ignition key is at the vehicle ON position and are disengagedwhen said key is at other than the ON position;

a gear shift lever switch connected with said gear shift lever andhaving its contacts arranged so that they are engaged when said gearshift lever is shifted into a vehicle driving gear and separated whensaid gear shift lever is shifted into a vehicle non-driving gear;

a switch mechanically connected with said parking brake and havingcontacts which are mechanically engaged by said parking brake when saidparking brake is locked in the applied position and which are separatedby said parking brake when said parking brake is released from theapplied position;

' a motor condition sensing switch, the contacts of which are normallyengaged and are responsive to activation of a first relay; a first relayassociated with and positioned to act upon said contacts of said motorcondition sensing switch to cause same to separate when the vehiclemotor is off while said ignition key switch is at the ON position and tocause same to reengage when the vehicle motor is also on;

a vehicle motion initiating means switch connected with the means in thevehicle which initiates movement of the vehicle, which switch hascontacts that are normally disengaged and which are engaged by operationof the vehicle movement initiating means in a manner which firstinitiates the vehicle movement;

whereby when said contacts of all of said switches of said first circuitare engaged, said parking brake locking mechanism is released to releasesaid parking brake from the applied position.

24. In the movable vehicle having parking brakes and a parking brakelocking mechanism release means of claim 23,

said first circuit further including an uphill travel rollbackprevention switch means comprising, in electrical parallel; a gravitycontrolled switch means the contacts of which are adapted to be engagedwhen the vehicle is on a level surface and when the vehicle is to movedownhill on an incline and the contacts of which are adapted to bedisengaged when the vehicle is to move uphill, and a vacuum switchconnected to the vehicle induction manifold and whose contacts areadapted to be engaged upon a reduction of pressure in the inductionmanifold.

25. In the movable vehicle having parking brakes and a parking brakelocking mechanism release means of claim 23,

said first circuit including a gravity controlled switch means; saidgravity controlled switch means compr1s1ng:

a gear shift lever position responsive switch adapted to be selectivelyengageable with one of two grave ty controlled switch devices which areconnected in electrical parallel;

said gear shift lever switch being connected with a first gravitycontrolled switch device when the gear a shift lever is in one of theforward motion gears, and being connected with the second such switchdevice when the gear shift lever is in a rearward motion gear;

said first gravity controlled switch having its contacts so arrangedthat they are disengaged when the vehicle is facing uphill and engagedwhen the vehicle is on a level surface and when it is facing downhill; 7

said second gravity controlled switch having its contacts so arrangedthat they are disengaged when the vehicle is facing uphill and engagedwhen the vehicle is on a level surface and when it is facing uphill.

26. In the movable vehicle having parking brakes and a parking brakelocking mechanism release means of claim 25,

both said first and said second gravity controlled switch devices beingmercury switches with the fixed contact being positioned to be contactedby the movable mercury contact when the vehicle is respectively facingother than uphill and other than downhill.

27. In the movable vehicle having parking brakes and a parking brakelocking mechanism release means of claim 23,

said vehicle motion initiating means comprising an accelerator pedalthat is adapted to move into engagement with and to then operate a rodconnected with the vehicle throttle, which rod, when operated, causesthrottle operation;

means for supporting said accelerator pedal a predetermined distanceaway from said throttle rod; v

said vehicle movement initiating means switch being positioned to engagesaid accelerator pedal when that said pedal is held away from saidthrottle rod; that said switch being so positioned that as soon as saidaccelerator pedal is moved toward said throttle rod, the contacts ofthat said switch are caused to be engaged.

28. In the movable vehicle having a parking brake, a

parking brake locking mechanism and a release means for said lockingmechanism of claim 23,

a second relay which is connected through a second electric circuit to afirst relay; said second relay having contacts which, when engaged,complete the second circuit to said first relay, and which, whenseparated, break said second circuit to said first relay;

a power supply connected to said first relay through a third electriccircuit including said second relay and said ignition key switch; whensaid contacts of said ignition key switch are engaged and said contactsof said second relay are engaged, said second circuit is completed andsaid first relay is activated and said contacts of said motor conditionsensing switch are se arated; said second rel y being connected with themotor of said vehicle such that when said motor is operating, saidcontacts of said second relay are separated and said second circuit tosaid first relay is broken thereby deactivating said first relay,

' which, in turn, permits said contacts of said motor condition sensingswitch to be normally biased into engagement, which permits said firstelectric circuit of said electrically operable mechanism to becompleted.

29. In the movable vehicle having a parking brake, a parking brakelocking mechanism and a release means for said locking mechanism ofclaim 23,

said electrically operable mechanism comprising a solenoid device havinga plunger connected to said locking mechanism, and said solenoid deviceand plunger thereof being positioned to engage said locking mechanismand cause same to be released when said first circuit, which isconnected to operate upon said solenoid device, is completed.

30. In the movable vehicle having a parking brake, a parking brakelocking mechanism and a release means for said locking mechanism ofclaim 29,

said solenoid device being connected to said power supply through thecontacts of a third relay; said contacts of said third relay beingnormally separated; said third relay being connected with said firstelectric circuit such that when said first electric circuit iscompleted, said contacts of said third relay are engaged and the circuitto said solenoid device is completed.

1. In a movable vehicle having foot brakes operated by a foot brakepedal, a foot brake locking mechanism for locking the foot brakes in thebrakes applied position; said locking mechanism including anelectrically operable mechanism for locking said brakes; saidelectrically operable mechanism being connected to a power source bymeans of a first electric circuit, which first circuit must be completedbefore said electrically operable mechanism will cause said foot brakesto lock; said first circuit including a plurality of switches, with eachswitch including cooperating contacts, which cooperating contacts ofeach switch must be engaged to complete said first circuit; saidswitches are: an ignition key switch, the contacts of which are engagedwhen said vehicle ignition key is at the vehicle ''''ON'''' position andare separated when said key is at other than the vehicle ''''ON''''position; a switch connected with said vehicle gear shift lever andhaving its contacts arranged so that they are engaged when said gearshift lever is shifted into a vehicle non-driving gear and separatedwhen said gear shifT lever is shifted into a vehicle driving gear; aswitch responsive to the position of the brake pedal, the contacts ofwhich are closed when the brake pedal is depressed; a switchmechanically connected with said locking mechanism and having contactswhich are caused to be mechanically engaged by said locking mechanismwhen said locking mechanism is deactivated and which are caused to bedisengaged by said locking mechanism when said locking mechanism isactivated, whereby once said locking mechanism is activated, saidcontacts of that said switch separate and said first electric circuit isbroken, thereby preventing unneeded power loss and prematuredeterioration of said electrically operable mechanism; whereby when saidcontacts of all of said switches are engaged, said locking mechanism isactivated to lock said brake pedal in the brakes applied position; afoot brake locking mechanism release means including a secondelectrically operable mechanism; said second electrically operablemechanism being connected to a power source by means of a secondelectric circuit, which second circuit must be completed before saidsecond electrically operable mechanism will cause release of said footbrake locking mechanism; said second circuit including a plurality ofswitches, with each switch having cooperating contacts which must beengaged to complete said second circuit; said second circuit switchesincluding: said ignition key switch; a second gear shift lever switchconnected with said gear shift lever and having its contacts arranged sothat they are engaged when said gear shift lever is shifted into avehicle driving gear and separated when said gear shift lever is shiftedinto a vehicle non-driving gear; a second switch mechanically connectedwith said locking mechanism and having contacts which are mechanicallyengaged by said locking mechanism when said locking mechanism isactivated and which are separated by said locking mechanism when saidlocking mechanism is deactivated; a first motor condition sensingswitch, the contacts of which are normally engaged and are responsive toactivation of a first relay; a first relay associated with andpositioned to act upon said contacts of said first motor conditionsensing switch to cause same to separate when the vehicle motor is offwhile said ignition key switch is at the ''''ON'''' position and tocause same to reengage when the vehicle motor is also on; a vehiclemovement initiating means switch connected with the means in the vehiclewhich initiates movement of the vehicle, which switch has contacts thatare normally disengaged and which are engaged by operation of thevehicle movement initiating means in a manner which will initiatevehicle movement; whereby when said contacts of all of said switches ofsaid second circuit are engaged, said foot brake pedal locking mechanismrelease means is activated to release said brake pedal from said lockingmechanism.
 2. In the movable vehicle having foot brakes and a foot brakelocking mechanism release means of claim 1, said vehicle motioninitiating means comprising an accelerator pedal that is adapted to moveinto engagement with and to then operate a rod connected with thevehicle throttle, which rod, when operated, causes throttle operation;means for supporting said accelerator pedal a predetermined distanceaway from said throttle rod; said vehicle movement initiating meansswitch being positioned to engage said accelerator pedal when that saidpedal is held away from said throttle rod; that said switch being sopositioned that as soon as said accelerator pedal is moved toward saidthrottle rod, the contacts of that said switch are caused to be engaged.3. In the movable vehicle having foot brakes and a foot brake lockingmechanism release means of claim 1, said second circuit furtherincluding an uphill travel rollback prevention switch means comprising,in electrical parallel: a gravity controlled switch mEans the contactsof which are adapted to be engaged when the vehicle is on a levelsurface and when the vehicle is to move downhill on an incline and thecontacts of which are adapted to be disengaged when the vehicle is tomove uphill, and a vacuum switch connected to the vehicle inductionmanifold and whose contacts are adapted to be engaged upon a reductionof pressure in the induction manifold.
 4. In the movable vehicle havingfoot brakes and a foot brake locking mechanism release means of claim 1,said vehicle having a parking brake which is applied by manual means bythe vehicle operator, a locking mechanism for holding said parking brakein the applied position after it has been manually applied, and aparking brake locking mechanism release means; said parking brakelocking mechanism including a holding device for engaging and holdingsaid parking brake in the applied position; said parking brake lockingmechanism release means including a third electrically operablemechanism for releasing said parking brake from said second holdingdevice; said third electrically operable mechanism being connected to apower source by means of a third electric circuit, which third circuitmust be completed before said third electrically operable mechanism willcause release of said parking brake; said third circuit including aplurality of switches, with each switch having cooperating contactswhich must be engaged to complete said third circuit; said third circuitswitches including: said ignition key switch; said second gear shiftlever switch; a third switch mechanically connected with said parkingbrake and having contacts which are mechanically engaged by said parkingbrake when said parking brake is locked in the applied position andwhich are separated by said parking brake when said parking brake isreleased from the applied position; a second motor condition sensingswitch, the contacts of which are normally engaged and are responsive toactivation of a second relay; a second relay associated with andpositioned to act upon said contacts of said second motor conditionsensing switch to cause same to separate when the vehicle motor is offwhile said ignition key switch is at the ''''ON'''' position and tocause same to reengage when the vehicle motor is also on; said vehiclemotion initiating means switch; whereby when said contacts of all ofsaid switches of said third circuit are engaged, said parking brakelocking mechanism is released to release said parking brake from theapplied position.
 5. In the movable vehicle having parking brakes and aparking brake locking mechanism release means of claim 4, said thirdcircuit further including an uphill travel rollback prevention switchmeans comprising, in electrical parallel; a gravity controlled switchmeans the contacts of which are adapted to be engaged when the vehicleis on a level surface and when the vehicle is to move downhill on anincline and the contacts of which are adapted to be disengaged when thevehicle is to move uphill, and a vacuum switch connected to the vehicleinduction manifold and whose contacts are adapted to be engaged upon areduction of pressure in the induction manifold.
 6. In the movablevehicle having parking brakes and a parking brake locking mechanismrelease means of claim 4, said vehicle motion initiating meanscomprising an accelerator pedal that is adapted to move into engagementwith and to then operate a rod connected with the vehicle throttle,which rod, when operated, causes throttle operation; means forsupporting said accelerator pedal a predetermined distance away fromsaid throttle rod; said vehicle movement initiating means switch beingpositioned to engage said accelerator pedal when that said pedal is awayfrom said throttle rod; that said switch being so positioned that assoon as said accelerator pedal is moved toward said throttle rod, thecontacts of that said switch are caused to be engaged.
 7. In the movablevehicle having brakes of claim 1, said first circuit further including amanually operable switch, the contacts of which are engageable andseparable by the vehicle operator; said manually operable switch beingconnected in electrical parallel to said switch connected with saidvehicle gear shift lever.
 8. In the movable vehicle having brakes ofclaim 1, said first circuit further including an inertia controlledswitch the contacts of which are closed upon the vehicle halting afterundergoing rapid deceleration.
 9. In the movable vehicle having brakesof claim 8, wherein said inertia controlled switch is a mercury switchthe fixed contact of which is positioned to be contacted by the liquidmercury contact on the reaction motion of the vehicle when it is haltedafter rapid deceleration.
 10. In the movable vehicle having brakes ofclaim 8, said first circuit further including a manually operableswitch, the contacts of which are engageable and separable by thevehicle operator; said manually operable switch being connected inelectrical parallel to said switch connected with said vehicle gearshift lever.
 11. In the movable vehicle having brakes of claim 1, saidelectrically operable mechanism comprising a solenoid device having aplunger connected to said locking mechanism and being positioned tocause activation of said locking mechanism when said first circuit,which is connected to operate upon said solenoid device, is completed.12. In the movable vehicle having brakes of claim 11, said solenoiddevice being connected to said power supply through the contacts of afirst relay; said contacts of said first relay being normally separated;said first relay being connected with said first electric circuit suchthat when said first electric circuit is completed, said contacts ofsaid first relay are engaged and the circuit to said solenoid device iscompleted.
 13. In the movable vehicle having brakes of claim 11, saidfoot brake pedal being connected to a master cylinder hydraulic fluidsource and said fluid source being connected to the vehicle brakes,whereby depressing said foot brake pedal transmits fluid pressure to thevehicle brakes to brake the vehicle; said locking mechanism furthercomprising a flow switch interposed between said brake pedal and thevehicle brakes, which switch is selectively adjustable between a firstposition which permits one-way flow away from said brake pedal, therebyonly permitting said brake pedal to be depressed and the brakes to beapplied, and a second position which permits two-way flow both away fromand back towards said brake pedal; said solenoid device plunger beingconnected with said switch to cause same to shift to its said firstposition when said solenoid device is activated.
 14. In the movablevehicle having foot brakes operated by a foot pedal of claim 13, saidfoot brake locking mechanism release means; being connected with saidflow switch in a manner such that when said release means is activated,it causes said flow switch to shift to its said second position.
 15. Ina movable vehicle having foot brakes operated by a foot pedal, a footbrake locking mechanism; and a foot brake locking mechanism releasemeans; said release means including an electrically operable mechanismfor releasing said foot brakes from said locking mechanism; saidelectrically operable mechanism being connected to a power source bymeans of a first electric circuit, which first circuit must be completedbefore said electrically operable mechanism will cause release of saidbrakes; said first circuit including a plurality of switches, with eachswitch having cooperating contacts which must be engaged to completesaid first circuit; said switches including: an ignition key switch, thecontacts of which are engaged when the vehicle ignition key is at thevehicle ''''ON'''' position and are disengaged when said key is at otherthan the vehicle ''''ON'''' position; a gear sHift lever switchconnected with said gear shift lever and having its contacts arranged sothat they are engaged when said gear shift lever is shifted into avehicle driving gear and separated when said gear shift lever is shiftedinto a vehicle non-driving gear; a motor condition sensing switch, thecontacts of which are normally engaged and are responsive to activationof a first relay; a first relay associated with and positioned to actupon said contacts of said motor condition sensing switch to cause sameto separate when the vehicle motor is off while said ignition key switchis at the vehicle ''''ON'''' position and to cause same to reengage whenthe vehicle motor is also on; a switch mechanically connected with saidlocking mechanism and having contacts which are mechanically engaged bysaid locking mechanism when said locking mechanism is activated andwhich are separated by said locking mechanism when said lockingmechanism is deactivated; whereby once said locking mechanism isreleased under the influence of said electrically operable mechanism,said contacts of said switch that is mechanically connected with saidlocking mechanism separate and said first electric circuit is broken,thereby preventing unneeded power loss and premature deterioration ofsaid electrically operable mechanism; a vehicle movement initiatingmeans switch connected with the means in the vehicle which initiatesmovement of the vehicle, which switch has contacts that are normallydisengaged and which are engaged by operation of the vehicle movementinitiating means in a manner which will initiate vehicle movement;whereby when said contacts of all of said switches of said first circuitare engaged, said foot brake pedal locking mechanism release means isactivated to release said brake pedal from said locking mechanism. 16.In the movable vehicle having foot brakes and a foot brake lockingmechanism release means of claim 15, said first circuit furtherincluding an uphill travel rollback prevention switch means comprising,in electrical parallel; a gravity controlled switch means the contactsof which are adapted to be engaged when the vehicle is on a levelsurface and when the vehicle is to move downhill on an incline and thecontacts of which are adapted to be disengaged when the vehicle is tomove uphill, and a vacuum switch connected to the vehicle inductionmanifold and whose contacts are adapted to be engaged upon a reductionof pressure in the induction manifold.
 17. In the movable vehicle havingfoot brakes and a foot brake locking mechanism release means of claim15, said first circuit including a gravity controlled switch means; saidgravity controlled switch means comprising: a gear shift lever positionresponsive switch adapted to be selectively engageable with one of twogravity controlled switch devices which are connected in electricalparallel; said gear shift lever switch being connected with a firstgravity controlled switch device when the gear shift lever is in one ofthe forward motion gears, and being connected with the second suchswitch device when the gear shift lever is in a rearward motion gear;said first gravity controlled switch having its contacts so arrangedthat they are disengaged when the vehicle is facing uphill and engagedwhen the vehicle is on a level surface and when it is facing downhill;said second gravity controlled switch having its contacts so arrangedthat they are disengaged when the vehicle is facing uphill and engagedwhen the vehicle is on a level surface and when it is facing uphill. 18.In the movable vehicle having foot brakes and a foot brake lockingmechanism release means of claim 17, both said first and said secondgravity controlled switch devices being mercury switches with the fixedcontact being positioned to be contacted by the movable mercury contactwhen the vehicle is respectively facing other than uphill and other thandownhill.
 19. In the movable vehicle having foot brakes and a foot brakelocking mechanism release means of claim 15, said vehicle motioninitiating means comprising an accelerator pedal that is adapted to moveinto engagement with and to then operate a rod connected with thevehicle throttle, which rod, when operated, causes throttle operation;means for supporting said accelerator pedal a predetermined distanceaway from said throttle rod; said vehicle movement initiating meansswitch being positioned to engage said accelerator pedal when that saidpedal is held away from said throttle rod; that said switch being sopositioned that as soon as said accelerator pedal is moved toward saidthrottle rod, the contacts of that said switch are caused to be engaged.20. In the movable vehicle having foot brakes, a foot brake lockingmechanism and a release means for said locking mechanism of claim 15,said electrically operable mechanism comprising a solenoid device havinga plunger connected to said brake locking mechanism and being positionedto move said locking mechanism away from said brakes applied positionwhen said first circuit, which is connected to operate upon saidsolenoid device, is completed.
 21. In the movable vehicle having footbrakes, a foot brake pedal locking mechanism and a release means forsaid locking mechanism of claim 15, a second relay which is connectedthrough a second electric circuit to said first relay; said second relayhaving contacts, which, when engaged, complete the second circuit tosaid first relay, and which, when separated, break said second circuitto said first relay; a power supply connected to said first relaythrough a third electric circuit including said second relay and saidignition key switch; when said contacts of said ignition key switch areengaged and said contacts of said second relay are engaged, said secondcircuit is completed and said first relay is activated and said contactsof said motor condition sensing switch are separated; said second relaybeing connected with the motor of said vehicle such that when said motoris operating, said contacts of said second relay are separated and saidsecond circuit to said first relay is broken thereby deactivating saidfirst relay, which, in turn, permits said contacts of said motorcondition sensing switch to be normally biased into engagement, whichpermits said first electric circuit of said electrically operablemechanism to be completed.
 22. In the movable vehicle having footbrakes, a foot brake locking mechanism and a release means for saidlocking mechanism of claim 21, said solenoid device being connected tosaid power supply through the contacts of a third relay; said contactsof said third relay being normally separated; said third relay beingconnected with said first electric circuit such that when said firstelectric circuit is completed, said contacts of said third relay areengaged and the circuit to said solenoid device is completed.
 23. In amovable vehicle having a parking brake which is applied by manual meansby the vehicle operator, a locking mechanism for holding said parkingbrake in the applied position after it has been manually applied, and aparking brake locking mechanism release means; said parking brakelocking mechanism including a holding device for engaging and holdingsaid parking brake in the applied position; said release means includingan electrically operable mechanism for releasing said parking brake fromsaid holding device; said electrically operable mechanism beingconnected to a power source by means of a first electric circuit, whichfirst circuit must be completed before said electrically operablemechanism will cause release of said parking brake; said first circuitincluding a plurality of switches, with each switch having cooperatingcontacts which must be engaged to complete said first circuit; saidswitches including: an ignition key switch, the contacts of which areengaged when said vehicle ignition key is At the vehicle ''''ON''''position and are disengaged when said key is at other than the''''ON'''' position; a gear shift lever switch connected with said gearshift lever and having its contacts arranged so that they are engagedwhen said gear shift lever is shifted into a vehicle driving gear andseparated when said gear shift lever is shifted into a vehiclenon-driving gear; a switch mechanically connected with said parkingbrake and having contacts which are mechanically engaged by said parkingbrake when said parking brake is locked in the applied position andwhich are separated by said parking brake when said parking brake isreleased from the applied position; a motor condition sensing switch,the contacts of which are normally engaged and are responsive toactivation of a first relay; a first relay associated with andpositioned to act upon said contacts of said motor condition sensingswitch to cause same to separate when the vehicle motor is off whilesaid ignition key switch is at the ''''ON'''' position and to cause sameto reengage when the vehicle motor is also on; a vehicle motioninitiating means switch connected with the means in the vehicle whichinitiates movement of the vehicle, which switch has contacts that arenormally disengaged and which are engaged by operation of the vehiclemovement initiating means in a manner which first initiates the vehiclemovement; whereby when said contacts of all of said switches of saidfirst circuit are engaged, said parking brake locking mechanism isreleased to release said parking brake from the applied position.
 24. Inthe movable vehicle having parking brakes and a parking brake lockingmechanism release means of claim 23, said first circuit furtherincluding an uphill travel rollback prevention switch means comprising,in electrical parallel; a gravity controlled switch means the contactsof which are adapted to be engaged when the vehicle is on a levelsurface and when the vehicle is to move downhill on an incline and thecontacts of which are adapted to be disengaged when the vehicle is tomove uphill, and a vacuum switch connected to the vehicle inductionmanifold and whose contacts are adapted to be engaged upon a reductionof pressure in the induction manifold.
 25. In the movable vehicle havingparking brakes and a parking brake locking mechanism release means ofclaim 23, said first circuit including a gravity controlled switchmeans; said gravity controlled switch means comprising: a gear shiftlever position responsive switch adapted to be selectively engageablewith one of two gravity controlled switch devices which are connected inelectrical parallel; said gear shift lever switch being connected with afirst gravity controlled switch device when the gear shift lever is inone of the forward motion gears, and being connected with the secondsuch switch device when the gear shift lever is in a rearward motiongear; said first gravity controlled switch having its contacts soarranged that they are disengaged when the vehicle is facing uphill andengaged when the vehicle is on a level surface and when it is facingdownhill; said second gravity controlled switch having its contacts soarranged that they are disengaged when the vehicle is facing uphill andengaged when the vehicle is on a level surface and when it is facinguphill.
 26. In the movable vehicle having parking brakes and a parkingbrake locking mechanism release means of claim 25, both said first andsaid second gravity controlled switch devices being mercury switcheswith the fixed contact being positioned to be contacted by the movablemercury contact when the vehicle is respectively facing other thanuphill and other than downhill.
 27. In the movable vehicle havingparking brakes and a parking brake locking mechanism release means ofclaim 23, said vehicle motion initiating means comprising an acceleratorpedal that is adapted to move into engagement with and to tHen operate arod connected with the vehicle throttle, which rod, when operated,causes throttle operation; means for supporting said accelerator pedal apredetermined distance away from said throttle rod; said vehiclemovement initiating means switch being positioned to engage saidaccelerator pedal when that said pedal is held away from said throttlerod; that said switch being so positioned that as soon as saidaccelerator pedal is moved toward said throttle rod, the contacts ofthat said switch are caused to be engaged.
 28. In the movable vehiclehaving a parking brake, a parking brake locking mechanism and a releasemeans for said locking mechanism of claim 23, a second relay which isconnected through a second electric circuit to a first relay; saidsecond relay having contacts which, when engaged, complete the secondcircuit to said first relay, and which, when separated, break saidsecond circuit to said first relay; a power supply connected to saidfirst relay through a third electric circuit including said second relayand said ignition key switch; when said contacts of said ignition keyswitch are engaged and said contacts of said second relay are engaged,said second circuit is completed and said first relay is activated andsaid contacts of said motor condition sensing switch are separated; saidsecond relay being connected with the motor of said vehicle such thatwhen said motor is operating, said contacts of said second relay areseparated and said second circuit to said first relay is broken therebydeactivating said first relay, which, in turn, permits said contacts ofsaid motor condition sensing switch to be normally biased intoengagement, which permits said first electric circuit of saidelectrically operable mechanism to be completed.
 29. In the movablevehicle having a parking brake, a parking brake locking mechanism and arelease means for said locking mechanism of claim 23, said electricallyoperable mechanism comprising a solenoid device having a plungerconnected to said locking mechanism, and said solenoid device andplunger thereof being positioned to engage said locking mechanism andcause same to be released when said first circuit, which is connected tooperate upon said solenoid device, is completed.
 30. In the movablevehicle having a parking brake, a parking brake locking mechanism and arelease means for said locking mechanism of claim 29, said solenoiddevice being connected to said power supply through the contacts of athird relay; said contacts of said third relay being normally separated;said third relay being connected with said first electric circuit suchthat when said first electric circuit is completed, said contacts ofsaid third relay are engaged and the circuit to said solenoid device iscompleted.